+ if (!has_cache) { + spin_lock(&si->lock);I'm no expert on that code, but we might drop the cluster lock the take the swap_info lock and then retake the cluster lock. I assume there are no races we are worrying about here, right?I suppose so. Even the original single-entry code follows the same pattern: static unsigned char __swap_entry_free(struct swap_info_struct *p, swp_entry_t entry) { struct swap_cluster_info *ci; unsigned long offset = swp_offset(entry); unsigned char usage; ci = lock_cluster_or_swap_info(p, offset); usage = __swap_entry_free_locked(p, offset, 1); unlock_cluster_or_swap_info(p, ci); if (!usage) free_swap_slot(entry); return usage; } I assume that once we mark them as SWAP_HAS_CACHE, no one else will touch them except ourselves.
That makes sense, thanks! -- Cheers, David / dhildenb
